Malleability of the Mind
Imagine you are age sixty-five. You are supposed to be relishing your golden years when suddenly, out of nowhere, you suffer a debilitating stroke. Rather than surrender to the illness and become a prison of your own body you decide to rebel. Even though you have severely limited mobility and little coordination, you force yourself to accomplish mundane tasks such as sweeping a porch. Slowly but surely you regain a firm grasp on your faculties. You are even able to return to teaching for another five years. Each day you up the ante on physical challenges and by the age of seventy-three, you are able to fulfill another test—climb the mountains of Colombia.
This was the plight and success story of Paul Bach-y-Rita’s father, Pedro. After suffering from and dying of a myocardial infarction during the trek up to the aforesaid mountains of Colombia, an autopsy revealed that the senior Bach-y-Rita withstood massive brain damage caused mainly not by the heart attack but by the stoke suffered eight years prior. The devastation was so vast, it was incredible that Pedro had even made a recovery let alone what seemed to be a full one. On the contrary, everyone else assumed that he had only sustained a little brain damage. So what could have been responsible for the full recovery of his cognitive abilities despite great and irreversible brain damage? This neurobiology conundrum is what persuaded Paul to change medical careers from a researcher of the visual sciences to a professor of rehabilitation medicine at the University of Wisconsin. Furthermore, Paul wanted to recreate the “miracle” he witnessed in his father. Paul’s research and innovations have no doubt contributed greatly to the world of neuroscience and pioneered the once taboo and now fledgling field of neuroplasticity.
So what is neuroplasticity? Just as what the name hints at, it is the belief that the brain is plastic, a malleable organ. As science writer, Sharon Begley explained in a February 2007 NPR program, neuroplasticity is based on the idea that one’s brain has the ability to physically alter itself through one’s personal experiences, the way one thinks, and the life one leads (1). Since the “brain is the organ of behavior” we can change brain structure simply through our thoughts and actions. These thoughts and actions “rewire” our brains by making new or different connections among neurons in various regions of the brain (1). In her book, Train Your Mind, Change Your Brain, Begley cites a study conducted at Harvard University that elucidated the notion of an ever-changing brain. Researchers of the study wanted to observe the effects on the motor cortex of the brain by actual, physical practice on a piano versus the effects on the motor cortex by imagining doing the same physical exercise. Two groups were employed: one that actually practiced on the piano and another that just looked at the musical notes and imagined playing them. Before and after each exercise, the motor cortex region was measured for expansion on every individual in both groups. By the end of the study, it was found that both groups displayed approximately the same expansion of the motor cortex thus suggesting that concentrating on doing something is comparable to actually practicing the activity in terms of information absorption by the brain (1). Another observation cited in her book about the plasticity of the brain, Begley mentions the power of cognitive behavior therapy. People suffering with depression learn how to “think themselves out of depression” by learning how to rationalize each thought (1). Therefore one thought will not eventually lead to an irrational, proportionally overblown logic that could potentially result in anxiety and depression. People who participated in this method were able to recover just as well as those who opted for medication instead. However, people who underwent cognitive behavior therapy displayed better prevention in a relapse than those who chose medication. The relapse rate among the therapy patients was reduced by two-thirds (1). Begley reasons that because the requirement for serotonin uptake by the brain is constant, patients who used medication were more likely to relapse because the medicinal regimen needed to be followed everyday. Patients who underwent therapy were less likely to relapse because they learnt how to think differently. This implies, according to Begley, that concentration has a more “enduring effect on the brain” than medication (1). The author is careful to add that “thinking one’s way out” of autism, schizophrenia, or Alzheimer’s may be impossible due to too much brain damage. Neuroplasticity works for the brain in recovering lost information from a damaged region by allotting that function to another, healthier region of the brain. It has been recently discovered that the brain can re-grow neurons (neurogenesis) which allows for the transfer of information (i.e. function) from one cranial region to another (1). These discoveries in neuroplasticity have since shattered long established notions of the brain. Since 1861 the findings of French neurologist Paul Broca have long suggested that particular regions of the brain housed particular functions that led to certain behaviors. His idea was first cemented after finding lesions on the frontal lobe of a speechless man (2). This led Broca to believe that the brain compartmentalizes functions (2). Indeed MRI and PET scans have shown that various regions of the normal brain activate when we experience certain emotions, learn, see faces, etc. (2) thus suggesting that neurological processes happen in specific parts of the brain and if a particular region is damaged, then the functions served in that region will be lost. Considering that neuroplasticity has debunked these conclusions of the brain’s deterministic nature, is it possible to regain functions that were once lost or never experienced?
Just as how his father regained mobility and cognitive ability following a massive stroke, Paul Bach-y-Rita has spent his career teaching the disabled through conditioning exercises to gain or regain a sense that was once lost. Bach-y-Rita firmly believes that the brain is a highly malleable organ so we must not settle on the idea that the brain cells that we were born with are the only brain cells we are ever going to have. Approximately ten percent of our human brain consists of neurons, the brain cells responsible for sending and receiving electrical signals (2). The other ninety percent is made up of glial cells whose function is still unclear (2). To send signals from the CNS, neurons release neurotransmitters that are accepted by specific target receptors. However, some glial cells have been known to take up and emit neurotransmitters and therefore act as free agents (2). Bach-y-Rita reasons that free floating glial cells are necessary in making new or different connections among regions of the brain because less change in the brain’s configuration would be required. He says “ ‘ it’s so much less cumbersome to have changes in this system than it is the whole wiring system’ ” (2). He believes that these glial cells are key to understanding where human intellect emerged (2). So in teaching or re-teaching patients to gain or regain a lost sense or function, Bach-y-Rita proves that it is all in the reassignment of these processes—reassigning these processes to a different, healthier part of the brain.
In the case of Roger Behm, a man who lost his sense of sight when he was young, regaining this sense is a job left to Paul Bach-y-Rita and BrainPort. This contraption uses tiny cameras on a pair of eyeglasses (to substitute for eyes in a blind patient) and a grid of electrodes to be place on the tongue. Information about light and dark colors from the surroundings are received by the cameras, converted into electrical signals, and then transmitted to the electrodes (3). When the nerve endings in the tongue receive the electrical impulses from the electrodes, information is carried via a different pathway than in a seeing person to the area of the brain concerned with touch. After time is spent on conditioning, the blind eventually perceive touch as sight (3). Behm equates the experience to the child’s game where one child uses his finger to draw an image on another child’s back and that child has to guess as to what the image is.
As for Cheryl Schiltz, she lost her sense of balance after taking an antibiotic that destroyed the tiny hairs in her inner ear responsible for maintaining balance. Similar to the BrainPort, Schiltz’s apparatus used an electrode grid for the tongue. However, the electrode grid is in a circular form and instead if tiny cameras on a pair of eyeglasses, her electrode is attached to an accelerometer inside a helmet (2). With every movement of the accelerometer, the circle on the grid would move likewise. In order to keep her balance, all Schiltz had to do was adjusts her movements to try to keep the circle balanced and centered on her tongue.
With the emerging and promising field of neuroplasticity,it is clear that humanity has yet to unlock all the deep and fundamental secrets of the ever-changing brain. As written by Begley and believed by the late Paul Bach-y-Rita, the brain is a resilient organ capable of changing for the sake of the body’s survival. Thinking is just as powerful as doing. Thinking about recovery has more enduring effects than medication alone. Most importantly, the brain is malleable enough to learn/ relearn senses that were once lost. The blind can now see through touch. The balance incapable can now coordinate through touch as well.
Refernces
(1) http://www.npr.org/templates/story/story.php?storyId=7131130 [1]
(2) http://discovermagazine.com/2003/jun/feattongue [2]
(3) http://www.cbsnews.com/stories/2007/01/18/eveningnews/eyeontech/main2373433.shtml [3]
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